The present invention generally concerns switches. More specifically, the present invention concerns microelectromechanical switches.
Switching operations are a fundamental part of many electrical, mechanical, and electromechanical applications. Microelectromechanical systems (MEMS) for switching applications have drawn much interest, especially within the last few years. Products using MEMS technology are widespread in biomedical, aerospace, and communication systems. Recently, the MEMS applications for radio frequency (RF) communication systems have gained even more attention because of the MEMS""s superior characteristics. RF MEMS have advantages over traditional active-device-based communication systems due to their low insertion loss, high linearity, and broad bandwidth performance.
The present invention is an electromagnetic energy, e.g., visible light, controlled low actuation voltage MEMS switch. Stimulation of photovoltaic diodes causes a switching that controls the flow of a signal. A metal or other suitable conductive pad moves freely up and down within brackets, without the need for deformation, in response to the diodes to either ground a signal or permit it to pass. The low activation voltage of the bracketed pad structure permits the use of a reasonable number of photovoltaic diodes to develop sufficient voltage for actuation of the switch, allowing the realization of the present electromagnetic energy, e.g., visible light, controlled MEMS switch in a minimized chip area. The photovoltaic diodes do not require an independent DC power source to operate the switch of the invention. Use of different wavelengths to excite different sets of diodes allows turning on and off of the switch of the invention.
In a preferred embodiment, the conductive pad electrically grounds a signal when the pad is located in a relaxed position (contacts closed). The pad is oriented for gravity to hold it in the relaxed position, but a voltage may assist the position and should be used where gravity or another force will not assist the contacts. Electromagnetic energy, e.g., visible light, stimulation through photovoltaic diodes provides a voltage to allow the signal to pass when a voltage serves to locate the pad in a stimulated position (contacts open). Voltage from the photovoltaic diodes are provided to electrodes that move the pad up and down with a low actuation voltage compared to known devices. The pad is not bent by the actuation voltage.